Display device having improved light emission and color reproducibility

ABSTRACT

An exemplary display device includes: a display panel; a color conversion panel overlapping the display panel; and an optical bonding layer positioned between the display panel and the color conversion panel. The color conversion panel includes: a substrate; a color conversion layer and a transmission layer positioned between the substrate and the display panel; a first capping layer having one side facing the color conversion layer and the transmission layer, and another side facing the display panel; a second capping layer positioned between the first capping layer and the display panel; and an optical layer positioned between the first capping layer and the second capping layer and/or between the second capping layer and the optical bonding layer. A refractive index of the optical layer is lower than at least one of a refractive index of the first capping layer and a refractive index of the second capping layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 16/353,996 filed on Mar. 14, 2019, which is acontinuation application of U.S. patent application Ser. No. 15/490,699filed on Apr. 18, 2017, which claims priority under 35 USC § 119 toKorean Patent Application No. 10-2016-0052887 filed on Apr. 29, 2016, inthe Korean Intellectual Property Office, the disclosures of which areincorporated herein in their entirety by reference.

BACKGROUND (a) Field

The present disclosure relates generally to display devices. Morespecifically, the present disclosure relates to display devices havingimproved light emission and color reproducibility.

(b) Description of the Related Art

Among display devices, there is a liquid crystal display in which afield generating electrode is positioned in one of two display panels. Aplurality of thin film transistors and a plurality of pixel electrodesare positioned in a matrix configuration on one display panel(hereinafter referred to as ‘a thin film transistor array panel’)included in the liquid crystal display. Color filters of red, green, andblue are positioned on the other display panel (hereinafter referred to‘a common electrode panel’), and a common electrode covers an entiresurface thereof.

However, in the display device, light loss is generated in a polarizerand the color filters. Accordingly, a display device including a colorconversion panel to realize the display device while reducing light lossand having high efficiency has been proposed.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY

Exemplary embodiments relate to a display device with an improved lightemission rate and color reproducibility.

A display device according to an exemplary embodiment of the presentinvention includes: a display panel; a color conversion paneloverlapping the display panel; and an optical bonding layer positionedbetween the display panel and the color conversion panel, wherein thecolor conversion panel includes: a substrate; a color conversion layerand a transmission layer positioned between the substrate and thedisplay panel; a first capping layer having one side facing the colorconversion layer and the transmission layer, and another side facing thedisplay panel; a second capping layer positioned between the firstcapping layer and the display panel; and an optical layer positionedbetween the first capping layer and the second capping layer and/orbetween the second capping layer and the optical bonding layer. Arefractive index of the optical layer is lower than at least one of arefractive index of the first capping layer and a refractive index ofthe second capping layer.

The optical layer may include a first optical layer positioned betweenthe first capping layer and the second capping layer, and a secondoptical layer positioned between the second capping layer and theoptical bonding layer.

The refractive index of the first optical layer may be lower than therefractive index of the first capping layer, and the refractive index ofthe second optical layer may be lower than the refractive index of thesecond capping layer.

The optical layer may include at least one of a fluorine-containingcopolymer, porous silica, a porous silicon oxide, a silicon oxide, aporous metal oxide, a porous polymer, and an acryl-based resin.

The first capping layer may include silicon nitride.

The second capping layer may include at least one of TiO₂, SiNx, SiOx,TiN, AlN, Al₂O₃, SnO₂, WO₃, and ZrO₂.

The refractive index of the first capping layer may be about 1.8 toabout 1.9, and the refractive index of the second capping layer may beabout 1.4 to about 1.9.

A thickness of the optical layer may be less than the thickness of theoptical bonding layer.

A ratio of the thickness of the optical bonding layer to the thicknessof the optical layer may be about 1:5 to 1:1.

The display device may be a curved display device.

The display panel may include: a first substrate; a thin film transistorpositioned on the first substrate; a pixel electrode connected to thethin film transistor; a common electrode arranged to form an electricfield with the pixel electrode; a roof layer overlapping the pixelelectrode; and a liquid crystal layer positioned in a plurality ofmicrocavities positioned between the pixel electrode and the roof layer.

The optical bonding layer may include a fluoroacryl-based resin.

A color filter positioned between the substrate and the color conversionlayer may be further included.

The color conversion layer may include a red color conversion layer anda green color conversion layer, and the red color conversion layer andthe green color conversion layer may each include a quantum dot.

The color conversion layer and the transmission layer may include ascattering member.

A display device according to an exemplary embodiment of the presentinvention includes: a display panel; a color conversion paneloverlapping the display panel; and an optical bonding layer positionedbetween the display panel and the color conversion panel, wherein thecolor conversion panel includes: a substrate; a color conversion layerand a transmission layer positioned between the substrate and thedisplay panel; a first capping layer positioned between the colorconversion layer and the transmission layer, and the display panel; asecond capping layer positioned between the first capping layer and thedisplay panel; and an optical layer positioned in at least one ofbetween the first capping layer and the second capping layer and betweenthe second capping layer and the optical bonding layer. At least one ofan interface of the first capping layer and the optical layer and aninterface of the second capping layer and the optical layer isconfigured to generate total reflection.

Light incident from the color conversion layer and the transmissionlayer toward the display panel may be totally reflected either betweenthe first capping layer and the optical layer or between the secondcapping layer and the optical layer.

The display device may be a curved display device.

The display panel may include: a first substrate; a thin film transistorpositioned on the first substrate; a pixel electrode connected to thethin film transistor; a common electrode forming an electric field withthe pixel electrode; a roof layer overlapping the pixel electrode; and aliquid crystal layer positioned in a plurality of microcavitiespositioned between the pixel electrode and the roof layer.

According to exemplary embodiments, a light emission rate and colorreproducibility of the display device are improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view of a display device according to anexemplary embodiment of the present invention.

FIG. 1B is a schematic cross-sectional view illustrating further detailsof certain elements of the present invention.

FIG. 2 is a top plan view of a pixel area according to an exemplaryembodiment of the present invention.

FIG. 3 is a cross-sectional view taken along line of FIG. 2.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

In order to clearly explain the present invention, portions that are notdirectly related to the present invention are omitted, and the samereference numerals are attached to the same or similar constituentelements through the entire specification.

In addition, the size and thickness of each configuration shown in thedrawings are arbitrarily shown for better understanding and ease ofdescription, but the present invention is not limited thereto. In thedrawings, the thickness of layers, films, panels, regions, etc., areexaggerated for clarity. In the drawings, for better understanding andease of description, the thicknesses of some layers and areas areexaggerated. The drawings are thus not to scale.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itcan be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present. Further,in the specification, the word “on” or “above” means positioned on orbelow the object portion, and does not necessarily mean positioned onthe upper side of the object portion based on a gravitational direction.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising” will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements.

Further, throughout the specification, the phrase “on a plane” meansviewing a target portion from the top, and the phrase “on across-section” means viewing a cross-section formed by verticallycutting a target portion from the side.

All numerical values are approximate, and may vary. All examples ofspecific materials and compositions are to be taken as nonlimiting andexemplary only. Other suitable materials and compositions may be usedinstead.

A display device according to an exemplary embodiment of the presentinvention will be described with reference to FIG. 1A to FIG. 4. FIG. 1Ais a cross-sectional view of a display device according to an exemplaryembodiment of the present invention, FIG. 1B is a schematiccross-sectional view illustrating further details of certain elements ofthe present invention, FIG. 2 is a top plan view of a pixel areaaccording to an exemplary embodiment of the present invention, FIG. 3 isa cross-sectional view taken along line of FIG. 2, and FIG. 4 is across-sectional view taken along line IV-IV of FIG. 2.

First, referring to FIG. 1A, a display device according to an exemplaryembodiment of the present invention includes a color conversion panel30, a display panel 10 overlapping the color conversion panel 30, and alight assembly 500 providing light to the color conversion panel 30 andthe display panel 10. The display panel 10 is positioned between thecolor conversion panel 30 and the light assembly 500. The colorconversion panel 30 and the display panel 10 may be combined by anoptical bonding layer 400.

The optical bonding layer 400 may be manufactured by coating a resin andperforming UV irradiation to the resin. In this case, about 95% or moreof a hardening of the resin is performed by the UV irradiation. Theoptical bonding layer 400 may include a fluoroaryl-based resin, howeverit is not limited thereto.

The display panel 10 does not include a separate column spacer. When thedisplay device is curved, it is difficult to maintain a cell gap of theliquid crystal layer, but in an exemplary embodiment of the presentinvention, when using the optical bonding layer 400 hardened by the UVirradiation, stable fixing and combination of the display panel 10 andthe color conversion panel 30 are possible. Accordingly, the displaydevice according to an exemplary embodiment of the present invention maybe provided as a curved type display panel.

Also, the optical bonding layer 400 according to an exemplary embodimentof the present invention may better prevent an edge lifting phenomenonbetween the display panel 10 and the color conversion panel 30, therebypreventing an unintended twist phenomenon of the display device.

The light assembly 500 may include a light source positioned under thedisplay panel 10 and generating light, and a light guide (not shown)receiving the light and guiding the received light in a direction towardthe display panel 10 and the color conversion panel 30.

As an example of the present invention, the light assembly 500 mayinclude at least one light emitting diode (LED), e.g. a blue lightemitting diode (LED). The light source of the present invention may bean edge-type light assembly disposed on at least one side of the lightguide plate, or may be a direct-type assembly where the light source ofthe light assembly 500 is positioned directly underneath the light guideplate (not illustrated), however it is not limited thereto.

Next, the color conversion panel 30 is described.

The color conversion panel 30 includes a plurality of color conversionlayers 330R and 330G, and a transmission layer 330B positioned between asubstrate 310 and the display panel 10.

The plurality of color conversion layers 330R and 330G may emit theincident light as light of different colors, and as an example, may be ared color conversion layer 330R and a green color conversion layer 330G.The transmission layer 330B may emit incident light without separatecolor conversion, and as an example, receives and transmits blue lightfrom the blue LEDs of the light assembly 500.

A light blocking member 320 may be positioned between the substrate 310and the display panel 10, and may be positioned at the same layer as thecolor conversion layers 330R and 330G and the transmission layer 330B.The light blocking member 320 is positioned between adjacent colorconversion layers, e.g. between any two adjacent ones of colorconversion layers 330R and 330G and the transmission layer 330B, andmore specifically, may define the region where the red color conversionlayer 330R, the green color conversion layer 330G, and the transmissionlayer 330B are disposed. The light blocking member 320, and the adjacentred color conversion layer 330R, green color conversion layer 330G, andtransmission layer 330B may partially overlap depending on themanufacturing process used.

The red color conversion layer 330R includes at least one of a phosphorand a quantum dot 331R for converting blue light that is incidentthereto into red light. When the red color conversion layer 330Rincludes a red phosphor, the red phosphor may contain one of (Ca, Sr,Ba)S, (Ca, Sr, Ba)2Si5N8, CaAlSiN3, CaMoO4, and Eu2Si5N8, but is notlimited thereto. The red color conversion layer 330R may include atleast one kind of red phosphor.

The green color conversion layer 330G includes at least one of aphosphor and a quantum dot 331G for converting blue light that isincident thereto into green light. When the green color conversion layer330G includes the green phosphor, the green phosphor may contain one ofyttrium aluminum garnet (YAG), (Ca, Sr, Ba)₂SiO₄, SrGa₂S₄, BAM,α-SiAlON, β-SiAlON, Ca₃Sc₂Si₃O₁₂, Tb₃Al₅O₁₂, BaSiO₄, CaAlSiON, and(Sr_(1-x)Ba_(x))Si₂O₂N₂, but the present disclosure is not limitedthereto. The green color conversion layer 330G may include at least onekind of green phosphor. In this case, the variable x may be any numberbetween 0 and 1.

The red color conversion layer 330R and the green color conversion layer330G may include a quantum dot for converting color instead of thephosphor, or may further include a quantum dot in addition to thephosphor. In this case, the quantum dot may be selected from a GroupII-VI compound, a Group III-V compound, a Group IV-VI compound, a GroupIV element, a Group IV compound, and any combination thereof.

The Group II-VI compound may be selected from a two-element compoundselected from CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe,MgS, and any mixture thereof; a three-element compound selected fromCdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS,CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe,MgZnS, and a mixture thereof; and a four-element compound selected fromHgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe,HgZnSeS, HgZnSeTe, HgZnSTe, and any mixture thereof. The Group III-Vcompound may be selected from a two-element compound selected from GaN,GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and anymixture thereof; a three-element compound selected from GaNP, GaNAs,GaNSb, GaPAs, GaPSb, AlNP, AINAs, AlNSb, AlPAs, AlPSb, InNP, InNAs,InNSb, InPAs, InPSb, and any mixture thereof; and a four-elementcompound selected from GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP,GaInNAs, GaInNSb, GaInPAs, GaInPSb, GaAlNP, InAlNP, InAlNAs, InAlNSb,InAlPAs, InAlPSb, and any mixture thereof. The Group IV-VI compound maybe selected from a two-element compound selected from SnS, SnSe, SnTe,PbS, PbSe, PbTe, and any mixture thereof; a three-element compoundselected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe,SnPbTe, and any mixture thereof; and a four-element compound selectedfrom SnPbSSe, SnPbSeTe, SnPbSTe, and any mixture thereof. The Group IVelement may be selected from Si, Ge, and any mixture thereof. The GroupIV compound may be a two-element compound selected from SiC, SiGe, andany mixture thereof.

In this case, the two-element compound, the three-element compound, orthe four-element compound may exist in particles at a uniformconcentration, or in the same particle while having differentconcentration distributions. Alternatively, they may have a core/shellstructure where one quantum dot encloses another quantum dot. Aninterface between the core and the shell may have a concentrationgradient such that a concentration of an element existing in the shellgradually decreases closer to a center of the interface.

The quantum dots 331R and 331G may have a full width at half maximum(FWHM) of the light-emitting wavelength spectrum that is equal to orless than about 45 nm, preferably equal to or less than about 40 nm, andmore preferably equal to or less than about 30 nm, and in this range,color purity or color reproducibility may be improved. In addition,since light emitted by the quantum dot is emitted in all directions, aviewing angle of light may be improved.

In addition, the quantum dot is not specifically limited to have shapesthat are generally used in the technical field related to the presentdisclosure, and more specifically, may have a shape such as anano-particle having a spherical shape, a pyramid shape, a multi-armshape, or a cubic shape, or may be a nanotube, a nanowire, a nanofiber,a planar nano-particle, etc.

The transmission layer 330B may include a resin that transmits bluelight incident thereto. The transmission layer 330B is positioned in aregion for emitting blue light, and thus emits the incident blue lightat it is without a separate phosphor or quantum dot. Although notillustrated herein, in some exemplary embodiments, the transmissionlayer 330B may further include a dye or pigment.

The above-described red color conversion layer 330R, green colorconversion layer 330G, transmission layer 330B, and light blockingmember 320 may include a photosensitive resin as an example, and may bemanufactured by a photolithography process. Alternatively, the red colorconversion layer 330R, the green color conversion layer 330G, thetransmission layer 330B, and the light blocking member 320 may bemanufactured by a printing process, and when manufactured by theprinting process, they may include materials other than thephotosensitive resin.

In the present specification, it is illustrated that the colorconversion layer, the transmission layer, and the light blocking layerare formed by a photolithography process or a printing process, but thepresent disclosure is not limited thereto.

At least one of the red color conversion layer 330R, the green colorconversion layer 330G, and the transmission layer 330B may include ascattering member 335. For example, the red color conversion layer 330R,the green color conversion layer 330G, and the transmission layer 330Bmay each include the scattering member 335, but embodiments are notlimited thereto. For example, the transmission layer 330B may includethe scattering member 335, while the red color conversion layer 330R andthe green color conversion layer 330G may not include the scatteringmember 335.

The scattering member 335 may include any material that can evenlyscatter incident light, and for example, may include one of TiO₂, ZrO₂,Al₂O₃, In₂O₃, ZnO, SnO₂, Sb₂O₃, and ITO.

On the other hand, referring to FIG. 1A, a red color filter 330R′ may bepositioned between the substrate 310 and the red color conversion layer330R, and a green color filter 330G′ may be positioned between thesubstrate 310 and the green color conversion layer 330G. The red colorfilter 330 R′ and the green color filter 330G′ may provide furtherimproved color reproducibility, however exemplary embodimentscontemplate both the presence and the absence of these additional colorfilters. Thus, for instance, the plurality of color filters 330R′ and330G′ may be omitted.

A first capping layer 350 a is located between the red color conversionlayer 330R, the green color conversion layer 330G, the transmissionlayer 330B, and the light blocking member 320 on the one end, and thedisplay panel 10 on the other.

The first capping layer 350 a prevents damage to and extinction of thephosphor or the quantum dot in the red color conversion layer 330R andthe green color conversion layer 330G, due to high temperature processesused in the formation of these color conversion layers.

The first capping layer 350 a may include an inorganic material, and asan example, a silicon nitride (SiN_(x)). In this case, a refractiveindex of the first capping layer 350 a may be in a range of about 1.8 toabout 1.9.

A first optical layer 370 a is positioned between the first cappinglayer 350 a and the display panel 10. The first optical layer 370 a isdescribed further below.

Next, a second capping layer 350 b is positioned between the firstoptical layer 370 a and the display panel 10. The second capping layer350 b may be a filter transmitting light of a predetermined wavelength,and reflecting or absorbing light other than the predeterminedwavelength.

Although not shown, the second capping layer 350 b may have a structurein which a plurality of layers having different refractive indexes arestacked. The second capping layer 350 b may include at least one ofTiO₂, SiNx, SiOx, TiN, AlN, Al₂O₃, SnO₂, WO₃, and ZrO₂, and for example,may be a structure in which SiNx and SiOx are alternately stacked.

The second capping layer 350 b may include a structure in whichinorganic films having a high refractive index and inorganic filmshaving a low refractive index are alternately stacked about 10 to 20times, and utilize the above-described material. It may transmit or/andreflect the light of the specific wavelength by using reinforcementinterference and/or destructive interference between the inorganic filmhaving the high refractive index and the inorganic film having the lowrefractive index.

The refractive index of the second capping layer 350 b may be in therange of about 1.4 to about 1.9.

A second optical layer 370 b is positioned between the second cappinglayer 350 b and the optical bonding layer 400. In this exemplaryembodiment, the first optical layer 370 a and the second optical layer370 b are both present. However, embodiments are not limited thereto,and an exemplary embodiment only including the first optical layer 370 aor only the second optical layer 370 b is possible. That is, the displaydevice according to an exemplary embodiment of the present invention mayinclude an optical layer 370 positioned either between the first cappinglayer 350 a and the second capping layer 350 b, between the secondcapping layer 350 b and the optical bonding layer 400, or both.

The optical layer 370 may include at least one among afluorine-containing copolymer, porous silica, a porous silicon oxide, asilicon oxide, a porous metal oxide, a porous polymer, and anacryl-based resin, however it is not limited thereto, and any materialsatisfying the predetermined refractive index is also possible. Further,the optical layer 370 may be manufactured without method limitation suchas through an inkjet method, a coating method, or a slit method.

Next, the optical layer 370, including the first optical layer 370 a andthe second optical layer 370 b, is described in detail.

The first optical layer 370 a has a lower refractive index than thefirst capping layer 350 a. The refractive index of the first cappinglayer 350 a may be in a range of about 1.8 to 1.9, and the first opticallayer 370 a may have a refractive index of about 1.8 or less.

The red color conversion layer 330R, the green color conversion layer330G, and the transmission layer 330B emit the light in all directions.In this case, in the color conversion panel 30, the light incident fromthe direction of the display panel 10 corresponds to light loss,accordingly it is necessary to again reflect the light in a userdirection.

Referring to FIG. 1B, the light incident passing through the highrefractive index first capping layer 350 a falls incident to the lowrefractive index first optical layer 370 a, such that light incident ata larger angle than a threshold angle may be again reflected backthrough the first capping layer 350 a according to a principle of totalreflection. That is, total reflection is generated in an interfacebetween the first capping layer 350 a and the first optical layer 370 a.Accordingly, light direction is reflected back toward the user, therebyincreasing the light emission rate of the display device.

Next, the second optical layer 370 b has a lower refractive index thanthe second capping layer 350 b. The refractive index of the secondcapping layer 350 b may be in a range of about 1.4 to about 1.9, suchthat the second optical layer 370 b may have a refractive index of about1.4 or less.

Like the above-described principle, light passing through the higherrefractive index second capping layer 350 b falls incident to the lowerrefractive index second optical layer 370 b, and light incident at alarger angle than a threshold angle may be reflected back up through thesecond capping layer 350 b. That is, total reflection is generated atthe interface of the second capping layer 350 b and the second opticallayer 370 b.

The above-described first optical layer 370 a and second optical layer370 b may respectively include different materials. Accordingly, thefirst optical layer 370 a may include a material having a lowerrefractive index than the first capping layer 350 a, and the secondoptical layer 370 b may include a material having a lower refractiveindex than the second capping layer 350 b.

Further, the first optical layer 370 a and the second optical layer 370b may include the same material. The first optical layer 370 a and thesecond optical layer 370 b have a lower refractive index than therefractive index of the first capping layer 350 a. Also, the firstoptical layer 370 a and the second optical layer 370 b have a lowerrefractive index than the refractive index of the second capping layer350 b. In this way, when having the lower refractive index than eachcapping layer 350, the refractive indices of each of the first opticallayer 370 a and the second optical layer 370 b may be less than about1.4.

On the other hand, the optical layer 370 may be thinner than the opticalbonding layer 400. The thickness of the optical bonding layer 400 may bein a range of about 1 μm to about 5 μm, and the thickness of each of thefirst optical layer 370 a and the second optical layer 370 b may be lessthan about 1 μm to about 5 μm. In this case, the thickness of the firstoptical layer 370 a and the thickness of the second optical layer 370 bare independent. However, when the optical bonding layer 400 is about 5μm thick, in the case that the thickness of the first optical layer 370a is about 3 μm and the thickness of the second optical layer 370 b isabout 4 μm, total reflection may be effectively achieved.

Also, a ratio of the thickness of the optical bonding layer 400 to thethickness of the optical layer 370 may be about 1:5 to about 1:1. Indetail, the ratio of the thickness of the optical bonding layer to thethickness of the first optical layer may be about 1:5 to 1:1, and theratio of the thickness of the optical bonding layer to the thickness ofthe second optical layer may be about 1:5 to 1:1. In this case of thethickness ratio, further improved light emission efficiency may beobtained.

In summary, to form the display device including the display panel 10and the color conversion panel 30 to be a curved display device, stablecombination of the two panels 10 and 30 and high temperature reliabilityis preferably obtained, and the optical bonding layer 400 is requiredfor this. The optical bonding layer 400 may cause partial light loss.However, the color conversion panel including the optical layeraccording to an exemplary embodiment of the present invention increasesthe light amount emitted in the user direction by employing totalreflection generated between the capping layer and the optical layer,thereby improving the light emission rate and the color reproducibility.

Next, the display panel 10 will be described with reference to FIG. 2 toFIG. 4.

The display panel 10 may include a liquid crystal panel 50 displaying animage, and polarizers 12 and 22 positioned on respective surfaces of theliquid crystal panel 50. The first polarizer 12 and the second polarizer22 for polarizing the light incident from the light assembly 500 arepositioned on respective (here, opposing) surfaces of the liquid crystalpanel 50.

The present specification describes a display panel forming a verticalelectric field, however the display panel is not limited thereto, and itmay be a liquid crystal panel forming a horizontal electric field, aplasma display panel (PDP), an organic light emitting diode display(OLED), a surface conduction electron-emitter display (SED), a fieldemission display (FED), a vacuum fluorescent display (VFD), an E-paper,etc.

As an example, the display panel 10 forming a vertical electric fieldwill be described in further detail below.

FIG. 2 shows a 2×2 pixel arrangement corresponding to a plurality ofmicrocavities 305, and the display device according to an exemplaryembodiment of the present invention may have these pixels repeatedlyarranged both vertically and horizontally.

The liquid crystal panel 50 according to an exemplary embodiment of thepresent invention includes a gate line 121 positioned on a firstsubstrate 110, and the gate line 121 includes a gate electrode 124.

A gate insulating layer 140 is positioned on the first substrate 110 andthe gate line 121. A semiconductor layer 151 positioned under a dataline 171 and a semiconductor layer 154 positioned under source/drainelectrodes 173 and 175 and corresponding to a channel part of the thinfilm transistor Q are positioned on the gate insulating layer 140.

Data conductors 171, 173, and 175, i.e. the data line 171 including thesource electrode 173 and the drain electrode 175, are positioned on thesemiconductor layers 151 and 154 and the gate insulating layer 140.

The gate electrode 124, the source electrode 173, and the drainelectrode 175 form a thin film transistor Q along with the semiconductorlayer 154, and the channel of the thin film transistor Q is formed inthe semiconductor layer 154 between the source electrode 173 and thedrain electrode 175.

A first passivation layer 180 a may be positioned on the data conductors171, 173, and 175 and an exposed portion of the semiconductor layer 154.The first passivation layer 180 a may include an inorganic insulator oran organic insulator such as a silicon nitride (SiNx) and a siliconoxide (SiOx).

A light blocking layer 220 and a second passivation layer 180 b arepositioned on the first passivation layer 180 a.

The light blocking layer 220 is formed to have a lattice structureprovided with an opening corresponding to an area for displaying animage, and is made of a material that does not transmit light. Thesecond passivation layer 180 b may include an inorganic insulator ororganic insulator such as silicon nitride (SiNx) and silicon oxide(SiOx).

The first and second passivation layers 180 a and 180 b and the lightblocking member 220 have a contact hole 185 exposing the drain electrode175.

A pixel electrode 191 is positioned on the second passivation layer 180b. The pixel electrode 191 may be made of a transparent conductivematerial such as ITO or IZO.

The pixel electrode 191 may have an overall quadrangular shape, and mayinclude a protrusion 197 protruding toward the thin film transistor Q.The protrusion 197 may be physically and electrically connected to thedrain electrode 175 through the contact hole 185.

The above-described thin film transistor Q and pixel electrode 191 arejust examples, and the structures of the thin film transistor and thedesign of the pixel electrode are not limited thereto. These structuresand designs may be changed in various ways while remaining consistentwith embodiments of the invention.

A lower alignment layer 11 is positioned on the pixel electrode 191, andan upper alignment layer 21 is positioned to overlap the lower alignmentlayer 11. The lower alignment layer 11 and the upper alignment layer 21may be vertical alignment layers. The lower alignment layer 11 mayinclude at least one among generally-used materials such as polyamicacid, polysiloxane, or polyimide.

In the present exemplary embodiment, an alignment material forming thealignment layers 11 and 21 and liquid crystal molecules 31 may beinjected into the microcavities 305 by using a capillary force. In thepresent exemplary embodiment, the lower alignment layer 11 and the upperalignment layer 21 are only divided depending on the position, as shownin FIG. 4, and may be connected to each other. The lower alignment layer11 and the upper alignment layer 21 may be simultaneously formed.

The microcavities 305 are positioned between the lower alignment layer11 and the upper alignment layer 21, and the liquid crystal molecules 31injected into the microcavities 305 form a liquid crystal layer 3.

The plurality of microcavities 305 may be arranged in a matrix format.Microcavities 305 adjacent in a Y direction may be separated ordistinguished from each other by a plurality of liquid crystal inlets307FP overlapping the gate lines 121. Microcavities 305 adjacent in an Xdirection may be distinguished from each other by partition wallportions PWP. Each of the microcavities 305 may correspond to one ormore pixel areas, and the pixel areas may correspond to an area fordisplaying an image.

A common electrode 270 and a third passivation layer 340 are positionedon the upper alignment layer 21. The common electrode 270 receives acommon voltage, generates an electric field along with the pixelelectrode 191 receiving a data voltage, and thereby determines adirection in which the liquid crystal molecules 31 positioned in themicrocavities 305 between the two electrodes are inclined. The commonelectrode 270 forms a capacitor along with the pixel electrode 191, suchthat the applied voltage is maintained after the thin film transistor isturned off. The third passivation layer 340 may be formed of siliconnitride (SiNx) or silicon oxide (SiOx).

In the present exemplary embodiment, the common electrode 270 ispositioned on the microcavities 305, however the common electrode 270may be positioned under the microcavities 305 as another exemplaryembodiment to realize liquid crystal driving according to a coplanarelectrode (CE) mode.

A roof layer 360 is positioned on the third insulating layer 340. Theroof layer 360 serves as a support so that the microcavity 305, which isa space between the pixel electrode 191 and the common electrode 270, isformed. The roof layer 360 may include a photoresist, or other organicmaterials.

A fourth passivation layer 380 is positioned on the roof layer 360. Thefourth passivation layer 380 may be in contact with an upper surface ofthe roof layer 360, and may be omitted depending on an exemplaryembodiment.

In the present exemplary embodiment, the partition wall portion PWP ispositioned between microcavities 305 adjacent in the X direction. Thepartition wall portion PWP may be formed along the Y-axis direction asthe direction in which the data line 171 extends, and may be covered bythe roof layer 360. The partition wall portion PWP is filled with thecommon electrode 270, the third insulating layer 340, the roof layer360, and the fourth insulating layer 380, and the microcavities 305 maybe divided or defined by this structure, which forms a partition wall.

A capping layer 390 is positioned on the fourth passivation layer 380.The capping layer 390 includes organic material or inorganic material.In the present exemplary embodiment, the capping layer 390 may also bepositioned in a liquid crystal inlet 307FP as well as on the fourthpassivation layer 380. In this case, the capping layer 390 may cover theliquid crystal inlet 307FP of the microcavity 305.

In the display device according to an exemplary embodiment of thepresent invention, the light emission rate and the color reproducibilityare improved such that a display device with excellent display qualitymay be provided and a substrate of one sheet may be used, therebysimplifying the manufacturing process and the structure.

Next, a light emission rate of the display device according to exemplaryembodiments of the present invention and a comparative example will bedescribed with reference to Table 1.

TABLE 1 Exemplary Exemplary Exemplary Comparative Embodiment 1Embodiment 2 Embodiment 3 example Light 78% 76.4% 81.8% 57.7% emissionrate

Exemplary Embodiment 1 relates to a display device including the firstoptical layer positioned between the first capping layer and the secondcapping layer, Exemplary Embodiment 2 relates to a display deviceincluding the second optical layer positioned between the second cappinglayer and the optical bonding layer, and Exemplary Embodiment 3 relatesto a display device including both the first optical layer and thesecond optical layer. The comparative example relates to the displaydevice in which the color conversion panel and the display panel areconnected through the optical bonding layer and does not include theoptical layer, a configuration that is different from the exemplaryembodiments.

Referring to this, in the case of Exemplary Embodiments 1 to 3 includingthe optical layer, it may be confirmed that the light emission rate ishigher than that of the comparative example by 20% or more. Also, amongthe plurality of exemplary embodiments, when the first optical layer andthe second optical layer are both included, it may be confirmed that thehighest light emission rate appears.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. Various features of the above describedand other embodiments can be mixed and matched in any manner, to producefurther embodiments consistent with the invention.

DESCRIPTION OF SYMBOLS

-   -   10: display panel    -   30: color conversion panel    -   400: optical bonding layer    -   310: substrate    -   330: color conversion layer    -   350 a, 350 b: first capping layer, second capping layer    -   370 a, 370 b: first optical layer, second optical layer

What is claimed is:
 1. A display device comprising: a color conversionpanel; light generating part; and an multilayer positioned between thelight generating part and the color conversion panel, wherein the colorconversion panel includes: a substrate; and a color conversion layer anda transmission layer positioned between the substrate and themultilayer; wherein the multilayer includes: a first layer overlappingthe color conversion layer and the transmission layer; and an secondlayer positioned between the first layer and the color conversion layer,wherein a refractive index of the second layer is lower than arefractive index of the first layer.
 2. The display device of claim 1,wherein the refractive index of the first layer is about 1.8 to about1.9, and the refractive index of the second layer is about 1.8 or less.3. The display device of claim 1, wherein the first layer includesinorganic material or silicon nitride.
 4. The display device of claim 1,wherein the second layer includes at least one of a fluorine-containingcopolymer, porous silica, a porous silicon oxide, a silicon oxide, aporous metal oxide, a porous polymer, and an acryl-based resin.
 5. Thedisplay device of claim 1, wherein the second layer is also positionedbetween the first layer and the transmission layer.
 6. The displaydevice of claim 5, wherein the multilayer further includes another firstlayer and another second layer, wherein the another first layer and theanother second layer positioned between the second layer and the colorconversion layer, and wherein the another first layer contacts thesecond layer.
 7. The display device of claim 6, wherein a refractiveindex of the another first layer is about 1.4 to about 1.9, and arefractive index of the another second layer is about 1.4 or less. 8.The display device of claim 1, wherein the transmission layer transmitsblue light from a light assembly.
 9. The display device of claim 1,further comprising: a color filter positioned between the substrate andthe color conversion layer.
 10. The display device of claim 9, whereinthe color conversion layer includes a red color conversion layer and agreen color conversion layer, and the red color conversion layer and thegreen color conversion layer each include a quantum dot.
 11. The displaydevice of claim 10, wherein the color filter comprises a red colorfilter overlapping the red color conversion layer, and a green colorfilter overlapping the green color conversion layer.
 12. The displaydevice of claim 1, wherein the color conversion layer and thetransmission layer include a scattering member.
 13. A display devicecomprising: a color conversion panel; light generating part; and anmultilayer positioned between the light generating part and the colorconversion panel, wherein the color conversion panel includes: asubstrate; a color conversion layer and a transmission layer positionedbetween the substrate and the multilayer; wherein the multilayerincludes: a first layer overlapping the color conversion layer and thetransmission layer; and a second layer positioned between the firstlayer and the color conversion layer, and wherein the first layerincludes inorganic material and the second layer includes monomer. 14.The display device of claim 13, wherein the first layer includes siliconnitride.
 15. The display device of claim 13, wherein the multilayerfurther includes: a third layer positioned between the second layer andthe color conversion layer.
 16. The display device of claim 15, whereinthe third layer includes inorganic material.
 17. The display device ofclaim 13, wherein a refractive index of the first layer is about 1.8 toabout 1.9, and a refractive index of the second layer is about 1.8 orless.
 18. The display device of claim 13, wherein the second layer isalso positioned between the first layer and the transmission layer. 19.The display device of claim 13, wherein the transmission layer transmitsblue light from a light assembly.
 20. The display device of claim 13,further comprising: a color filter positioned between the substrate andthe color conversion layer.
 21. The display device of claim 20, whereinthe color conversion layer includes a red color conversion layer and agreen color conversion layer, and the red color conversion layer and thegreen color conversion layer each include a quantum dot.
 22. The displaydevice of claim 21, wherein the color filter comprises a red colorfilter overlapping the red color conversion layer, and a green colorfilter overlapping the green color conversion layer.
 23. The displaydevice of claim 13, wherein the color conversion layer and thetransmission layer include a scattering member.
 24. A display devicecomprising: a color conversion panel; a light generating part; and acapping layer positioned between the light generating part and the colorconversion panel, wherein the color conversion panel includes: asubstrate; a color conversion layer and a transmission layer positionedbetween the substrate and the capping layer; and a color filter overlapcolor conversion layer, wherein a color conversion layer includes afirst conversion layer including a first quantum dot and a secondconversion layer including a second quantum dot, wherein a color filterincludes a first color filter and a second color filter, and wherein thefirst conversion layer overlaps the first color filter, and the secondconversion layer overlaps the second color filter.
 25. The displaydevice of claim 24, wherein the capping layer has a structure in whichlayers having different refractive indexes are stacked.
 26. The displaydevice of claim 25, wherein the capping layer includes at least one ofTiO2, SiNx, SiOx, TiN, AlN, Al2O3, SnO2, WO3, and ZrO2.
 27. The displaydevice of claim 24, further comprising a first capping layer and asecond capping layer, wherein the first capping layer includes inorganicmaterial, and the second capping layer includes silicon nitride.
 28. Thedisplay device of claim 27, wherein a refractive index of the firstcapping layer is about 1.8 to about 1.9, and a refractive index of thesecond capping layer is about 1.4 to about 1.9.
 29. The display deviceof claim 24, wherein the transmission layer transmits blue light from alight assembly.